In one conventionally known structure of a hybrid vehicle, a motor generator is located between an automatic transmission and a torque converter for transmission of the output power of an internal combustion engine to a driveshaft (see, for example, Patent Document 1). With a view to preventing deterioration of a catalyst for purification of exhaust gas emitted from the internal combustion engine, the hybrid vehicle of this structure performs control of prohibiting fuel cutoff to the internal combustion engine in a higher temperature condition of the catalyst over a preset reference value. The fuel cutoff in the high temperature condition of the exhaust gas purification catalyst may cause the catalyst to be exposed to a lean atmosphere at the high temperature and to be deteriorated. The control in the hybrid vehicle of this conventional structure prohibits the fuel cutoff to the internal combustion engine at the high temperature condition of the catalyst to control deterioration of the catalyst, even in the event of a deceleration request by the driver's accelerator-off operation in a preset condition. In order to compensate for an insufficiency of deceleration due to the prohibition of the fuel cutoff, the motor generator is activated to generate the regenerative braking force, and the regenerative electric power is accumulated in an accumulator, such as a secondary battery. In this conventional hybrid vehicle, in response to a deceleration request by the driver's accelerator-off operation at the high temperature condition of the catalyst, when there is a fear of making the regenerative electric power generated by the motor generator exceed an allowable charging power of the accumulator, a hydraulic brake is used to generate a required braking force, instead of the regenerative braking force by the motor generator.    Patent Document 1: Japanese Patent Laid-Open No. 2003-207043